Introduction Soldering copper pipes is a basic plumbing skill that once mastered will enable you to tackle many home repair and home improvement projects - for instance, replacing copper water lines or installing a new spigot. It can be as much an art as it is a science, thus the more you get the "feel for it", the faster and easier it gets.

Soldering copper pipe, or "sweating" as they call it in the trades, relies on capillary action to create a well-sealed joint. By using a propane torch to heat up the two pieces you are joining, solder is "sucked" into the joint and spreads evenly between the pipe and fitting. Once it cools, you should have a solid, leak-free joint that will last for years.

Use care when working with a torch. Keep the flame away from wood framing or other flammable materials. Also remember to let your work cool before handling it.

CautionsAlways use lead-free solder and rosin flux for plumbing projects.

Always use caution when using a torch near wood. Cover the wood with a piece of sheet metal to prevent direct exposure to the torch flame.

Use brush to apply flux and do not have flux come in contact with your eyes or skin. Excessive use of flux may corrode pipe or fittings.

Common MistakesDon't be in a hurry. If you don't properly prepare the pipes for soldering you may end up with leaks. Then you will need to completely drain the water out of the pipes you are working on. It is impossible to solder pipes with water in them.

Helpful TipsBefore you solder the pipes together, assemble all the pieces to make sure you have a proper fit and no unforeseen problems.

Pipes cannot be soldered if water is in them. Water prevents the pipes from reaching a hot enough temperature to melt solder. Try to drain as much water out of the existing water lines before beginning. Use a piece of bread (without its crust) and shove it in the pipe to hold back a gradual flow of water. The bread will dissolve when the water is turned back on.

1.

Plan ahead. Determine all the materials you will need to complete your plumbing project. Make sure you have enough copper tubing and fittings to make all your turns and straight runs. The last thing you want to do is run to the hardware store in the middle of a project.

2.

When you are ready to begin, cut all your straight pipes to length. (Make sure to add the length of straight pipe that will slide into each fitting.) A tubing cutter will give you the cleanest cut, however you can use a hacksaw and a miter box if necessary. However you decide to cut the pipe, make sure you do not bend the pipe or create nicks in the surface that will be soldered. These situations can cause leaks.

A tubing cutter is a clamp-like cutter that rotates around the pipe as you cut. Align the blade of the tubing cutter with your cut mark. Tighten the clamp in place. Spin the cutter around the pipe a few times, tightening it after each full rotation. Repeat until the cut is complete.

3.

Use the reaming blade on the tubing cutter to remove the bur on the inside of the cut pipe.

4.

Now you need to prepare the surfaces that will be soldered. Take emery cloth and polish the ends of the straight pieces where they will be soldered. Polish until the metal is shiny and clean. This will remove any grease, dirt and oxidation that can prevent a leak-free joint.

5.

Use a round wire brush to polish the insides of fittings.

6.

Before you start soldering, assemble your pieces to make sure everything is cut correctly. Make sure all joints fit together without "torquing" or twisting. If straight pipes do not slide easily into fittings, make sure they are not squashed into an oval shape. Recut any pipes that don't fit well. Disassemble the pipes and use the flux brush to put a thin coat of flux on all surfaces that will be soldered. This includes the ends of straight pipes and inside of fittings. Assemble the pipes and fittings again.

7.

Get ready to solder. First make sure that you protect all flammable materials near each joint. This includes wood framing, wiring and insulation. Cover the flammable materials with a piece of sheet metal. Next, take your roll of solder and unwind about 10 inches. Bend the last 2 inches into a 90-degree angle. Light your torch and adjust to a 1-1/2" flame. Heat the area on the fitting where the straight pipe slides into it. You want to use the inner flame tip and move it around slightly so that it heats the whole overlapping area. After heating for about 8 to 10 seconds, touch the solder to the joint at its highest point. If it is adequately heated, capillary action should pull solder into the joint. If solder does not pull into the joint, apply more heat and try again. When solder drips out of the bottom, the joint is filled with solder.

8.

For a clean, professional finish, quickly brush off any excess solder from around the joint. Be careful - the joint is still hot.

Once all joints are soldered and cooled, turn on the water to your new copper pipes. Open faucets to bleed any air from the system. Check your work for leaks. If you encounter leaks, you will need to re-solder those joints. It is important that you completely drain the water from the area. Otherwise the water will prevent the joint for heating up enough to melt the solder. First try reheating and applying new solder. If the leak persists, you will need to disassemble that joint and possibly replace a defective joint or pipe.

9.

To disassemble a joint, heat it up with your torch. While the joint is still hot, quickly grab the pipe and fitting with 2 pairs of pliers. Twist and pull the pipe and fitting apart. Be careful - they are hot! Using emery cloth you can clean the pipe and reuse. Do not reuse fittings. They are too difficult to completely clean for a leak-free joint.